This invention relates generally to an endless conveyor belt load measurement system and more particularly to such a system utilizing a digital computer and a method of automatically calibrating the system. This system was developed for use in measuring the amount of iron ore being transported by an endless conveyor belt, but it may be adapted for use in transporting a variety of other substances in other applications.
In the past, conveyor belt load measurement systems have commonly operated by having independent weight and speed measurement transmitters with analog outputs using various methods of combining the two analog output signals to provide a resulting load measurement output signal which is received by suitable indicating and recording mechanism. These previous systems are normally calibrated by having a skilled instrument technician separately calibrate the weight and speed transmitter and the recording mechanism. This method of calibration has the disadvantage that it is relatively expensive in that it requires the presence of the instrument technician and necessitates interruption of the load during the lengthy calibration period. Furthermore, the errors in calibration of the transmitters may be cummulative when the two transmitted signals are combined.
More recently, it has been suggested that calibration of these previous analog systems be provided by calibrating the combined analog signal in terms of actual measured load. While being an improvement, this has the disadvantage that with conventional instrumentation it is difficult to compensate for non-linearities in the combined weight and speed transmitted signals, and furthermore that a skilled instrumentation technician is still required to be on hand to provide this calibration.